OXY 5
Build Review by OXY Heli Addict

I wanted to write this OXY 5 build review firstly as I have been given this opportunity, secondly as it is my first larger size heli build. I have built the OXY 2, OXY 3 and OXY 4 Max. I’ve been flying for less than a year so I hope it will show that it is possible, with little experience, to build and fly your own RC heli. I belong to MK Heli Club where all the members are very helpful. I highly recommend joining a local heli club.

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Although the standard wizard setup Neo settings with a lowered tail gain are fine, I was able to ask members of my club; Richard Van Aken and Andy Kirby to fine tune my Neo (I will share settings later) and set up the Scorpion Tribunus ESC. READ the manual and carefully follow the steps if you choose to use the Scorpion Governor as I have. It’s a quick and easy process but requires certain steps in a specific order. The full VBC integration with the Scorpion app is great. I also use the battery logbook app. There’s no need to worry about flight timings as a preset warning advises during flight when the lipo voltage reaches the set discharged Voltage. Luca gives full electronics and power suggestions in the manual within a very useful chart. There is also actual Lynx pilot setups with headspeed information, dampener preference, blade size and much more useful info. I decided to go 6s with Lynx 550mm Main blades, 95mm Tail blades with standard size GDW servos. I also have the VTX 557 blades. Please note that if mini servos are used a separately available mini servo mount is required. I choose OptiPower and ManiaX 5000mAh lipos. I purchased everything from www.hely-shop.co.uk.

I downloaded the most recent (July 2019) manual from the Lynx website, I then gathered all the recommended tools required to complete the build which are listed within the first few pages of the manual.

Version: Beta 11. The whole instruction and assembly manual from Lynx Helicopters. Also available on their website.

Luca really knows how to guide you through a successful build and even offers Pro tips as you go with many setup recommendations. I will follow the steps exactly as outlined by Luca. All parts came pre assembled with some parts requiring threadlock. I used the Lynx medium strength. Each step is clearly defined with colourful images and Important notes which I follow carefully. The quality of the CNC parts is obvious and the precision cut carbon pieces are superb. Just like all other OXY’s the Oxy 5 build starts with the tail.

Tail parts to assemble

I used a 100% alcohol dip to clean all the screws before applying threadlock. It’s important to pay close attention to the manual when installing the tail belt. No twists or folds inside the boom, which I checked several times. I had too much side play on the tail shaft so I added an extra shim 6×8×0.1 that still allowed very slight play. Within no time at all I had completed the whole tail assembly.

Tail is done

The boom is solid and like all other OXY’s does not require a boom support and the CNC parts align perfectly. I then moved on to the frame assembly, which is a stepped frame with upper, middle and a lower bearing block. The canopy mounts are awesome and the quick release battery pin works perfectly. Although threadlock is added at this stage the screws should not be tightened until the next step, which is to install the main shaft with frame assembly on a flat surface, then push down on both frames together and fully tighten all Hex Cap Screws (×14) holding the upper and middle bearing blocks. Once the frame is together but with untightened screws the main shaft is put in place before pressure applied to the top and middle bearing blocks so the screws can be tightened fully.

Main frame

All parts lined up perfectly and although the main shaft was fairly smooth, mine didn’t fall through easily. This didn’t have any negative effect whatsoever as I continued with the build. It’s now quite obvious that the OXY 5 is going to be mahoosive compared to the OXY 4 Max. Also, It really is a fine quality heli with a well thought out and very versatile design. You may already have guessed I love OXY. I really hope the OXY 5 flight characteristics are similar to all the other OXY’s.

Rotorhead

The main gear hub comes assembled but the screws require threadlock. I used a single shim and still had slight vertical play. It was time to insert the boom and install the tail belt around the main gear hub. I had to slightly prize open the boom clamps so the boom would slide into its position. I then checked I had installed the belt correctly by rotating the main gear and making sure the tail hub turns the right way. Pay close attention to the next step which involves counter levering two hex tools to lift up the Lower Main Shaft Bearing block before tightening the screws. I could then set the belt tension by pulling the boom until I had around 1mm of deflection on the belt.

The heli now felt solid and I could start on the head assembly. The swash and main grips again highlight the precision and quality of Oxy CNC parts. Threadlock applied where required with a single shim on each grip and the head was super smooth. I used HSH dampening.

I was now ready to fit the Lynx servo horns to my GDW servos. Luca provides exact measurements for the Servo Rod Assembly and tells us which holes to use in the horns for cyclic and tail servos. I used a servo tester to center and found the swash-leveling tool very handy to set the swash and 3.5 degrees counter torque on the tail as I have done on all my OXY builds.

GDW servos

With all servos installed I mounted my Egodrift 4020 motor and fitted the standard 12T pinion before installing on the heli. Colourful images offer suggestions for wire routing and ESC installation. I really like the Omicron Double Face HD Adhesive Pad supplied in the accessories bag for mounting the ESC and Neo FBL unit. Luca also suggests where to use the supplied cable ties. I finally assembled the landing gear to complete the heli and then attached the battery hooks to the battery trays. Some very nice Lynx hook and loop straps are included with attractive OXY battery straps. A very nice touch! The battery system is intuitive and easy to use.

Scorpion Tribunus ESC for Egodrift Tengu motor

As with all other OXY builds I really enjoyed building the OXY 5. It was very similar to the already great pedigree of OXY’s fleet but larger screws and parts than the others made it easier. If building in a single sitting it would take around 4-5hrs. I have three children so mainly built in the evenings over a week. Lol. Below are my Neo settings. I am running 2100, 2250 and 2500 RPM head speed.

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